1. HESS observations of the Carina nebula and its enigmatic colliding wind binary Eta Carinae
- Author
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E. Birsin, G. Cologna, Nu. Komin, K. Egberts, Anna Szostek, S. J. Nolan, Joachim Hahn, Petter Hofverberg, K. Kosack, Konrad Bernlöhr, Heinrich J. Völk, M. Renaud, W. Kluźniak, P.-O. Petrucci, N. W. Pekeur, D. Nekrassov, G. Pühlhofer, M.-H. Grondin, J. Perez, A. Reimer, M. Naumann-Godo, M. Paz Arribas, P. Bordas, Dirk Lennarz, E. Moulin, A. Jacholkowska, Fabio Acero, A. Charbonnier, F. Feinstein, S. Heinz, C.-C. Lu, Andreas Quirrenbach, A. A. Zdziarski, Igor Oya, M. K. Daniel, S. Schwarzburg, M. Füßling, Stefan Ohm, Sarah Kaufmann, Ullrich Schwanke, Michael Zacharias, S. Pita, T. Bulik, I. Büsching, M. Dalton, L. Gérard, B. Glück, Anna Barnacka, Riaan Steenkamp, Matteo Cerruti, T. J. L. McComb, J. K. Becker, F. Krayzel, J. Dyks, A. G. Akhperjanian, G. Pelletier, S. Rosier-Lees, G. Heinzelmann, M. Mohamed, Regis Terrier, D. Klochkov, M. C. Medina, R. Kossakowski, Yvonne Becherini, B. Peyaud, A. Bochow, Werner Hofmann, Gilles Maurin, J. L. Skilton, Christo Venter, Marek Jamrozy, Andreas Hillert, M. V. Fernandes, D. Göring, R. White, A. Marcowith, Joachim Ripken, C. Jahn, Helene Sol, E. de Oña Wilhelmi, S. Häffner, A. Balzer, J. Bolmont, N. Nguyen, N. Maxted, I. Sushch, Michael Punch, Julien Masbou, Reinhard Schlickeiser, R. Moderski, J. Harris, A. Zech, Christian Stegmann, Isak Delberth Davids, M. Ostrowski, Peter Eger, Gisela Anton, A. Fiasson, Jim Hinton, L. Fallon, S. Schwemmer, Andrea Santangelo, C. van Eldik, V. Marandon, Hugh Dickinson, C. L. Naumann, David Sánchez, Gavin Rowell, Y. A. Gallant, H.-S. Zechlin, Daniel Hampf, M. Hauser, R. de los Reyes, Sabrina Casanova, F. Sheidaei, P. Espigat, Frank M. Rieger, Michal Dyrda, A. Abramowski, Ł. Stawarz, Francois Brun, G. Spengler, Francesca Volpe, J. D. Hague, B. Nicholas, André Schulz, J.-P. Tavernet, S. J. Fegan, A. Djannati-Ataï, Dieter Horns, J. Mehault, W. Domainko, Jacek Niemiec, Henning Gast, Pascal Vincent, A. Cheesebrough, Gerard Fontaine, Olaf Reimer, M. Mayer, K. Stycz, Jan Conrad, I. Jung, B. Rudak, A. Lopatin, B. Degrange, L. O'c. Drury, Anna Zajczyk, J. F. Glicenstein, Thierry Montmerle, M. de Naurois, Gilles Henri, J.-P. Lenain, F. Stinzing, Alicja Wierzcholska, B. Giebels, T. Garrigoux, Serguei Vorobiov, Krzysztof Katarzynski, M. J. Vorster, Markus Holler, Felix Aharonian, Pierre Brun, H. Laffon, K. Valerius, D. Nedbal, Thomas Lohse, M. Panter, U. Katz, M. Tluczykont, V. Sahakian, Martin Ward, C. B. Rulten, C. Boisson, B. Khélifi, G. Hermann, J. Brucker, G. Lamanna, R. C. G. Chaves, Aion Viana, B. Opitz, Jonathan Biteau, Guillaume Dubus, K. Dutson, Christoph Deil, T. Kneiske, L. Rob, Stefan Wagner, M. A. Kastendieck, G. Vasileiadis, P. M. Chadwick, A. Förster, Martin Raue, and Svenja Carrigan
- Subjects
Physics ,Colliding-wind binary ,Spectral index ,Nebula ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,Flux ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Particle acceleration ,Cover (topology) ,Space and Planetary Science ,0103 physical sciences ,Absorption (logic) ,Supernova remnant ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
The massive binary system Eta Carinae and the surrounding HII complex, the Carina Nebula, are potential particle acceleration sites from which very-high-energy (VHE; E > 100 GeV) \gamma-ray emission could be expected. This paper presents data collected during VHE \gamma-ray observations with the H.E.S.S. telescope array from 2004 to 2010, which cover a full orbit of Eta Carinae. In the 33.1-hour data set no hint of significant \gamma-ray emission from Eta Carinae has been found and an upper limit on the \gamma-ray flux of 7.7 x 10-13 ph cm-2 s-1 (99% confidence level) is derived above the energy threshold of 470 GeV. Together with the detection of high-energy (HE; 0.1 GeV > E > 100 GeV) \gamma-ray emission by the Fermi-LAT up to 100 GeV, and assuming a continuation of the average HE spectral index into the VHE domain, these results imply a cut-off in the \gamma-ray spectrum between the HE and VHE \gamma-ray range. This could be caused either by a cut-off in the accelerated particle distribution or by severe \gamma-\gamma\ absorption losses in the wind collision region. Furthermore, the search for extended \gamma-ray emission from the Carina Nebula resulted in an upper limit on the \gamma-ray flux of 4.2 x 10-12 ph cm-2 s-1 (99% confidence level). The derived upper limit of ~23 on the cosmic-ray enhancement factor is compared with results found for the old-age mixed-morphology supernova remnant W 28.
- Published
- 2012
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